Fix the Travis CI build.

The test file covers ghc-7.0.1 and above.

.travis.yml

 env:
- - GHCVER=6.12.3
- - GHCVER=7.0.1
- - GHCVER=7.0.2
- - GHCVER=7.0.3
- - GHCVER=7.0.4
- - GHCVER=7.2.1
- - GHCVER=7.2.2
- - GHCVER=7.4.1
- - GHCVER=7.4.2
- - GHCVER=7.6.1
- - GHCVER=7.6.2
- - GHCVER=7.6.3
+ - GHCVER=7.0.1 CABALVER=1.16
+ - GHCVER=7.0.2 CABALVER=1.16
+ - GHCVER=7.0.3 CABALVER=1.16
+ - GHCVER=7.0.4 CABALVER=1.16
+ - GHCVER=7.2.1 CABALVER=1.18
+ - GHCVER=7.2.2 CABALVER=1.18
+ - GHCVER=7.4.1 CABALVER=1.18
+ - GHCVER=7.4.2 CABALVER=1.18
+ - GHCVER=7.6.1 CABALVER=1.18
+ - GHCVER=7.6.2 CABALVER=1.18
+ - GHCVER=7.6.3 CABALVER=1.18
 
 before_install:
  - sudo add-apt-repository -y ppa:hvr/ghc
  - sudo apt-get update
- - sudo apt-get install cabal-install-1.18 ghc-$GHCVER
+ - sudo apt-get install cabal-install-$CABALVER ghc-$GHCVER
  - export PATH=/opt/ghc/$GHCVER/bin:$PATH
 
 install:
- - cabal-1.18 update
+ - cabal-$CABALVER update
+ - cabal-$CABALVER install --only-dependencies
+ - cabal-$CABALVER install "Cabal >= $CABALVER"
  - ghc --version
 
 script:
- - cabal-1.18 configure -v2
- - cabal-1.18 build
- - cabal-1.18 check
- - cabal-1.18 sdist
+ - cabal-$CABALVER configure -v2
+ - cabal-$CABALVER build -v2
+ - cabal-$CABALVER check
+ - cabal-$CABALVER sdist
 # The following scriptlet checks that the resulting source distribution can be built & installed
- - export SRC_TGZ=$(cabal-1.18 info . | awk '{print $2 ".tar.gz";exit}') ;
+ - export SRC_TGZ=$(cabal-$CABALVER info . | awk '{print $2 ".tar.gz";exit}') ;
    cd dist/;
    if [ -f "$SRC_TGZ" ]; then
-      cabal-1.18 install "$SRC_TGZ";
+      cabal-$CABALVER install "$SRC_TGZ";
    else
       echo "expected '$SRC_TGZ' not found";
       exit 1;

haskeline.cabal

 Name:           haskeline
-Cabal-Version:  >=1.6
+Cabal-Version:  >=1.16
 Version:        0.7.1.1
 Category:       User Interfaces
 License:        BSD3
@@ -59,7 +59,9 @@ Library
                        bytestring==0.9.*
     }
     Build-depends:  filepath >= 1.1 && < 1.4, transformers >= 0.2 && < 0.4
-    Extensions:     ForeignFunctionInterface, Rank2Types, FlexibleInstances,
+    Default-Language: Haskell98
+    Default-Extensions: 
+                ForeignFunctionInterface, Rank2Types, FlexibleInstances,
                 TypeSynonymInstances
                 FlexibleContexts, ExistentialQuantification
                 ScopedTypeVariables, GeneralizedNewtypeDeriving